This application is for the third competing renewal of our interdisciplinary pre-doctoral training program on The Molecular Pathogenesis of Infectious Diseases (MPID) at the University of Colorado Anschutz Medical Campus. Twenty-six faculty with affiliations in six departments offer our trainees opportunities to investigate molecular mechanisms that allow RNA and DNA viruses, Gram-positive and -negative bacteria, Mycobacterium tuberculosis, and protozoan parasites to cause morbidity and mortality in humans worldwide. MPID trainees have access to basic, genomic, computational, translational and systems biology research. Our training faculty have demonstrated productivity for innovative research in infectious diseases, illustrated by the fact that their labs receive an average of $750,000 per year in direct costs. Students are selected for appointment to this training program after they have completed their required coursework, passed their preliminary and comprehensive examinations, and begun their dissertation research. Since the initial award in 2002, the MPID program has funded 49 students, 8% of whom were underrepresented minorities. In the last 5 years, 90% of students affiliated with the MPID Training Program obtained undergraduate degrees from out-of-state institutions. The laboratories of training faculty expanded from 28 graduate students per year with an average of 3.4 publications per student in the previous funding period (2007-2013) to about 35 per year with an average of 4.6 publications per student in the last 4 years. In addition to completing coursework and conducting their mentored research projects, MPID students participate in and assume lead roles in seminars, journal clubs, research-in-progress meetings, and MPID mini-symposia and workshops. This comprehensive training prepares our students to identify important research questions, design well-controlled experiments incorporating cutting-edge approaches, critically evaluate and present their results, and understand and apply principles of ethics to their research. The breadth of the research, didactic, and leadership opportunities prepares MPID students for successful careers in academia, industry, and government. MPID graduates hold senior positions in industry (67%), faculty positions at academic institutions (15%), or government (6%). Twenty percent of trainees who have been affiliated with the MPID Training Program are currently pursuing postdoctoral fellowships in high ranked institutions, and 8% continue their medical education. Our trainees have secured NIH F31, F32, and R01 funding. Given the importance of training students in the broad field of infectious diseases, the successful record of the MPID Training Program, and the increased number of trainees and training faculty that our T32 has supported since it was awarded in 2002, we request support for an additional slot. This represents an increase of one to the four positions funded during the last 10 years, for five total slots per year.